Aquaculture—the farming of aquatic organisms—is a fast-growing venture that fills a gap between a diminishing supply of wild fish and world demand for seafood. As aquaculture expands globally and environmental regulations become more strict, the reuse of water is necessary both to meet regulation and to sustain production. However, aquaculture wastewater must be treated to be reused. Additionally, aquaculture sites are typically close to areas where discharge to surface waterways or municipal systems is the only option. See, generally, The State of World Fisheries and Aquaculture, by the Food and Agricultural Organization of the United Nations (FAO) Fisheries and Aquaculture Department, Rome, Italy, 2012 (209 pages).
Anaerobic digestion is one means by which municipalities treat waste water to reduce organic carbon and solids in volume and mass. Anaerobic digestion has been used to treat agricultural waste with varying rates of success. Anaerobic digestion of agricultural waste, and particularly of aquacultural wastewater, is difficult due to ammonia inhibition and solids concentration. While solids are commonly treated by dilution, this creates a very large volume of waste. Also, the physical removal of ammonia has not always proven satisfactory.